The UG4 gene is expressed in stem tissue and leaf tissue of the plant Arabidopsis thaliana. To study mechanisms regulating UG4 expression, six small deletions of DNA sequence upstream of the gene-coding sequence are made. The locations of deletions and their effect on UG4 expression are shown here. Why does deletion E lower expression of UG4 in leaf tissue but not in stem tissue?

Key Concepts

Gene Regulation

Gene regulation refers to the mechanisms that control the expression of genes, determining when and how much of a gene product is made. This process can involve various elements, including promoters, enhancers, and silencers, which interact with transcription factors to modulate gene activity in different tissues or developmental stages.

Tissue-Specific Expression

Tissue-specific expression is the phenomenon where certain genes are expressed in specific tissues while remaining inactive in others. This is often regulated by the presence of unique transcription factors or regulatory elements that respond to the cellular environment, allowing plants to adapt their gene expression profiles to different functional needs.

Deletion Mutations

Deletion mutations involve the removal of a segment of DNA, which can affect gene expression by altering regulatory regions. In the context of the UG4 gene, the specific deletion (E) may disrupt a regulatory element that is crucial for activating UG4 expression in leaf tissue, while leaving stem tissue unaffected due to different regulatory requirements or compensatory mechanisms.